This work was supported by the National Science Foundation of China (No.31500449),
West Light Foundation of the Chinese Academy of Sciences (No.XAB2015B05), Open
Fund of State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,
Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of
Water Resources (No.A314021402-1515), and the Fundamental Research Funds for the
Central Universities (No.2452016101). The funders had no role in study design, data
collection and analysis, decision to publish, or preparation of the manuscript.
; This work was supported by the National Science Foundation of China (No.31500449),
West Light Foundation of the Chinese Academy of Sciences (No.XAB2015B05), Open
Fund of State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,
Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of
Water Resources (No.A314021402-1515), and the Fundamental Research Funds for the
Central Universities (No.2452016101). The funders had no role in study design, data
collection and analysis, decision to publish, or preparation of the manuscript.

1.State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University2.State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources3.University of Chinese Academy of Sciences